1. Field of the Invention
This invention relates to a process for production of a glass substrate coated with a filnely patterned Nesa glass membrane or a transparent and electroconductive inorganic tin oxide film having a fine pattern on a glass substrate. The glass substrate coated with a finely patterned Nesa glass membrane is especially suitable for use as a flat panel in liquid crystal displays or plasma displays.
2. Description of Prior Art
Various processes are already known for the production of a glass substrate coated with a finely patterned Nesa glass membrane, among which is an etching process wherein a Nesa glass membrane is formed on the entire surface of a glass substrate by, for example, a spraying method; a metal mask or a photoresist mask is formed on the Nesa glass membrane; and then a pattern is formed by etching and removing the membrane according to the pattern, as is disclosed in Japanese Patent Application Laid-open No. 56-94542, No. 63-65090 or No. 63-171886.
According to this process, a pattern can be formed with high accuracy of about 30 .mu.m in line width or line separation, however, there is needed nascent hydrogen to effect the etching, and hence a concentrated mineral acid such as concentrated hydrochloric acid is needed. Thus, the method is not suitable for pratical use.
There is also known a lift off process wherein a glass substrate is masked with a masking paste by screen process printing; a Nesa glass membrane is formed thereon; and then the masking paste is washed and removed to leave a patterned Nesa glass membrane on the glass substrate. This process is simple and convenient, however, based on a limited fineness of the screen used and the viscosity of the paste has, the process has had a limit of accuracy of about 80 .mu.m in line width or line separation.